President Obama addresses Congress at 6 p.m. PT tonight in his second State of the Union speech. The event gives him the chance to recast his image in light of November's midterm elections that cost his Democratic Party control of the House of Representatives. Faced with a sour economy and a need to win over centrist voters, Obama will attempt to set the tone for his 2012 reelection bid.

Stanford political scientist Shanto Iyengar is weighing in on what to expect from the annual address. Iyengar, who is also the Harry & Norman Chandler Professor of Communication and director of the Political Communication Lab, focuses his teaching and research on the role of the news media and mass communication in contemporary politics. He is the author of several books, including Media Politics: A Citizen's Guide, which will be published in its second edition later this year.

The White House is saying the State of the Union address will sound different from years past. We know Obama will surely address the economy, but what other themes should we be watching for?

He needs to focus on jobs because that's the No. 1 concern. And he'll have to talk about working with Republicans. And he'll have to use the buzzwords like "bipartisanship" and "compromise." In general, he's not going to say anything that's aimed at the liberal arm of the party, and they're just going to have to suck it up. They're going to vote for him in any case. He's going to have to posture for the independents.

Christopher Dilts

President Obama, here with Vice President Biden, is expected to focus on the economy and jobs.

How will the president use the annual speech to further recast his image in light of the "shellacking" Democrats took in the midterm elections?

Given the results of the 2010 election, we can expect him to talk about shifting the administration's political stance in a more centrist direction. That was signaled earlier by the accomplishments of the lame-duck session of Congress, where Obama caved in on the Bush tax cuts and Republicans in return gave him the START treaty. That session of Congress demonstrated that the two parties could work together, and Obama's poll numbers went up. His approval numbers were at 43 percent after the election, and they're at 50 percent now. You can attribute that to the lame duck accomplishments. I don't think he'll say anything about the healthcare bill – it would be a mistake if he did. It's a polarizing issue, and he wants to get away from the image of being a polarizing figure.

In his State of the Union address last year, Obama said: "The only way to move to full employment is to lay a new foundation for long-term economic growth, and finally address the problems that America's families have confronted for years." Unemployment is still at 9 percent, but have those things happened?

There's evidence of at least some uptick in the economy. If there was ever going to be a real recovery, it's much more likely to happen in the aftermath of this year's speech than last year's speech. I would say he's got a good shot at telling people the end is in sight. Whether they believe him or not is up to their own experience and what they're seeing when it comes to their own pocketbooks. But generally speaking, consumer sentiment suggests that people are not as desperate as they were a year ago.

What role is the shooting rampage in Tucson playing in the tone of the address and the pageantry that surrounds it? Lawmakers from different parties will be sitting side by side rather than being divided by aisles, but does that signal a real desire to move toward bipartisan unity?

The shootings will definitely have an impact. There will certainly be multiple references to Congresswoman Giffords in the address. And it will lead to a kind of muted event. You're not going to see too many standing ovations. And I think partisanship will be not as overt as in years past. But it's all symbolism. These televised addresses are all exercises in image-making. There isn't anything substantive you can expect to come out of this.

How does a televised address like this impact public opinion?

Most evidence shows that it doesn't have any dramatic impact one way or the other. The only thing that it might accomplish is helping the president set the national agenda. But there's hardly any evidence that he's going to be able to change anyone's thinking of whether they should vote for him in the next election. The audience for these things is way down. In the 1970s, you had a captive and very large, nationwide audience. That was before the rise of cable. Now, most people are watching college basketball. The only people tuning in, for the most part, are those who already have strong political opinions.